Addition agents for mineral oil lubricants



Patented June 7, 1949 ADDITION AGENTS Foa MINERAL o LUBRICANTS Troy L. Cantrell, Lansdowne. and Herschel 0.

Smith, Wallingtord, Pa., minors to Golf Corporation, Pittsburgh,

Pennsylvania l'a., a corporation Serial No, 759,890

No Drawing. Application July 8,1941.

22 Claims.

, 1 This invention relates to addition agents for mineral oil lubricants, and more particularly, it relates to addition agents which confer improved bearing-corrosion inhibiting and detergent properties on mineral oil lubricants.

In the lubrication of internal combustion engines of all types, particularly when severe operating conditions are encountered, mineral lubricating oils frequentlyprove unsatisfactory because they tend to deposit varnish, gum and sludge on the engine surfaces, such as the cylinder walls, pistons and rings, and also to induce corrosion of bearing materials. These problems have become increasingly serious because of the trend toward higher efllciency or higher power output per unit weight of engine, which results in conditions tending to accelerate deteriorating influences on the mineral oil lubricant.

The formation of so-called varnishes and sludges on engine surfaces is a result of oxidation effects on the lubricating oils. The presence of such engine deposits is detrimental for many reasons. These substances increase ring sticking and accelerate the formation of further deposits on piston surfaces and fixed parts of the combustion chamber. The sludges formed in the crank case of the engine increase the rate of corrosion of bearing surfaces, especially of bearing alloys of the type now in use.

In the lubrication of steam turbines, the problems become more acute because of the presence of water in the mineral oiilubricant. Therefore, in addition to bearing corrosion, rusting may also be encountered.

It is an object of this invention, therefore, to provide an addition agent for mineral oil lubricants which will prevent the formation of the engine deposits encountered in the use of mineral oil lubricants.

It is a further object of this invention to provide addition agents for mineral oil lubricants which serve the functions of '(l) inhibiting the corrosion of bearings, (2) inhibiting rusting, and (3) acting as a detergent to prevent ring sticking, the formation of engine deposits and to suspend or disperse very small particles of deterioration products or contaminating materials in the lubricant.

These and other objects are achieved by the present invention wherein, as an addition agent for mineral oil lubricants. there is provided a salt having the following formula:

o fi on on I cm-qcrmgavg wherein R is an alkyl radical having from 4 to 12' carbon atoms, and M' is a divalent metal. The above salts are excellent detergents and in most instances are remarkably effective also for alkyl substituent of from 4'to 12 carbon atoms" with one mol of sulgur mono-chloride (S2Clz) The divalent metalsalts of the alkylated phenols used in preparing the addition agents of our invention are conveniently made by neutralizing the alkylated phenol with an oxide or hydroxide of the particular divalent metal desired. A1- ternatively, the alkali metal phenate of the phenol may first be made, and then the phenate maybe reacted with a water-soluble salt of the divalent metal to yield the divalent metal salt of the phenol by a double decomposition reaction. The phenol di-suliideused in making our new addition agents is prepared by reacting two mols of a para alkyl-phenol with one mol of sulfur mono-chloride according to the reaction:

on on on 0+ 8:01pOfi-O 21301 I The reaction of the sulfur mono-chloride with action, the prdd'ucti-foifiied t'e'ndstgt'ii be dark-'- colored and transmits toour new 'addition agents an undesirable dark-color and a tendency to be insoluble in mineral lubricating oils. The reaction of the para alkyl phenol-with the sulfur mono-chloride may take place in the presence of an inert solvent, such as benzenatpiuene, hexane, carbon tetrachloride," chlorcform.- 'cyclo hexane, etc., to obtain a lighterfcoldred.product' Also, the resulting phenol di-sulfide may be treated with a decolorizing clay, such as acid treated bentonite and the like, in "order to remove dark-colored byproducts.

The resulting phenol di-sulflde and the divalent metal salt of the para alkyl phenol are then condensed with formaldehyde. inthe proportions stated, with the-splitting Iofijdf two mols of water to yield our new addition agents. The condensation takes place upon heating, preferably to a temperature not greater than 275 F. In lieu of formaldehyde, formaldehyde-yielding compounds, such as trioxymethylene, paraformaldehyde and the like may be employed. Accordingly, as used in the appended claims, the term formaldehyde" is intended to include such formaldehyde-yielding substances, as well as formaldehyde itself. The phenols used in preparing both the divalent metal salt of the ,para alkyl phenol and the phenol di-sulfide-are-paraalkyl substituted phenols having from 4. to 12 carbon atoms-in the alkyl substituent. Thus, the ,alkyl substituent may include normal, or branched chain butyl, amyl, hexyl, heptyl, octyl, decyl and dodecyl radicals. A preferredalkyl substituent-is.the tetramethylbutyl radicaL- Theparaalkyl phenols are preferably obtained by alkylating in knownmanner, in the presence of concentrated .sulfuric acid, phenol with olefins having from.4 to 12 carbon atoms. Olefins such as butene-1,=.isobutylene, the amylenes, di-isobutylene and tri-isobutyiene may conveniently be employed. 'It is preferred to conduct the alkylation with di-isobutylenev since the resulting product is primarily a para tetramethylbutyl phenol.

Any divalent metalmay be used in forming the salt of the para alkyl. phenol'to yield excellent detergent compounds. Representative divalent metals include beryilium,-:'calcium, barium, magnesium, strontium. zinc, stannous tin, copper, lead, cobalt and nickel.- However, not all of the divalent metal salts of our invention confer hearing corrosion-inhibiting properties. Thus, copper and lead salts, although-providing excellent detergent properties, are ordinarily not as useful as the other salt's'of our invention for inhibiting bearingcorrosion.""Accordingly, a preferred sub-group of the divalent metals is the alkaline earth metals, since the salts of these metals confer both detergent and corrosion-inhibiting properties. Stannous salts are also excellent for both purposes. However, all of the divalent metal salts of our invention are excellent detergent agents; and therefore will confer detergent properties on mineraloll lubricants. If particular divalentrnetal saltsyvhich do .not have bearing corrosion-inhibiting properties are used in mineral oil lubricants for their detergent effects, other'materials, such as the calcium and barium salts of the present invention, or other known bearing corrosion inhibitors may be added to obtain the desired bearing corrosion-inhibiting effect. The metal salts of our invention are also potent rust inhibitors, and act as mild extreme pressure agents.

The following examples further illustrate our invention:

Example I.--Into a first enamel lined jacketed reaction vessel were charged 188 pounds of phenol, 240 pounds of di-isobutylene, and 9 pounds of 96 per cent sulfuric acid catalyst. The vessel was then 'closed and the contents were agitated, while passing cooling water through the jacket to prevent the reaction temperature from exceeding 220-F. Thetemperature was maintained at 220 F. for 12 hours. At the end of this period, a slurryof 84 pounds of hydrated lime in pounds of water was added to the para tetramethylbutyl phenol formed in the reaction vessel, resulting in the formation of the substantially neutral calcium salt of the para tetramethylbutyl phenol.

To a second enamel lined jacketed reaction vessel, there were added 188 pounds of phenol, 240 pounds of di-isobutylene and 9 pounds of 96 per cent sulfuric acid, and the temperature was maintained at 220 F. for 12 hours. At the end of this period, the resulting para tetramethylbutyl phenol was cooled to 60 F. and diluted with 400 pounds of hexane. Then 136 pounds of sulfur mono-chloride were added over a period of 3 hours. The byproduct (anhydrous hydrogen chloride) was vented to a hydrochloric acid recovery plant. The temperature was then raised to 140 R, where it was held for 10 hours.

The contents of the first reaction vessel were then charged into and mixed with the contents of the second reaction vessel, and 162 pounds of 37 per cent aqueous formaldehyde were added. The temperature was then raised to F. and held there for 4 hours. Then the mixture was allowed to settle, and the water layer was drawn off. The solvent layer was filtered through a continuous filter, and the filtrate distilled to remove the hexane solvent. The salt obtained had the following properties:

Per cent Sulfur 6.75 Ash, as oxide 5.90

The salt had the following formula:

0 \l on on Q-Cm-Q-CILQ -s-o vessel, there was added, at a temperature of 130 F., 1625 pounds of sulfur mono-chloride over a period of three hours. The temperature was then raised to 210 F. and held there for 18 hours. Byproduct hydrogen chloride was vented to a hydrochloric acid recovery plant. The resulting alkylated phenol di-sulfide was then diluted with 5060 pounds of a light lubricating oil having the following properties:

Gravity, API 30.4 Viscosity, SUV, 210 F. 43.5 Color, NPA 1.75 Neutralization No. nil

.consisting of the mineral oil solution of the alkylated phenol di-sulfide, was then mixed with the contents of the second reaction vessel along with 1458 pounds of 3'1 per cent aqueous formaldehyde. The mixture was agitated, heated to 210 F., and maintained at that temperature for 6 hours. Then the temperature was raised to 290 F. to remove all water and to dry the product. The dehydrated oil solution of the reaction product was filtered through a continuous filter and had the following properties:

Gravity, API e 15.4 Viscosity, SUV, 210 F. 336 Color, NPA 4.75 Sulfur, B per cent 3.3 Neutralization No. nil Ash as oxide per cent 3.0

Our new metal salts are excellent addition agents for mineral oil lubricating compositions. They are light-colored and readily soluble in all types of mineral oils,.that is, paramnic, naphthenic or mixed base mineral oils and, as a matter of fact, can be blended with mineral oils in proportions as high as 50 per cent by weight or higher. This excellent solubility of our new addition agents enables the preparation of concentrated solutions thereof, as shown in Example II, supra, which may then be diluted down to the proportion desired in the final mineral oil lubricant composition. As stated, our new addition agents confer excellent detergent effects on the mineral lubricating oils with which they are incorporated, and in most instances confer in addition excellent bearing corrosion-inhibiting and rust-inhibiting properties. For these purposes, our new addition agents are generally added to mineral oils in minor amounts, say from 0.1 per cent to 10.0 per cent by weight of the 'mineral oil, sufficient to confer improved detergent properties on the mineral lubricating oils with which they are incorporated. Generally, the addition of 1.0 per cent by weight of our new Base Oil gfi Gravity, API 28.2 27.7 Viscosity, SUV- 100 F 1, 585 1,670 210 F 66.4 67. 9 Viscosity Index 97 98 Flash, 0 F 480 475 40 Fire, 00, 1 555 550 Base 01] Improved Oil Pour, F -5 5.

Sulfur, Per Cantu... 0.03 0.18. Copper Strip Test, 212 F., 3 Hr. passes passes Corrosion Test, ASTM D665- 46T Distilled Water:

Steel Bod, Appearance rust bright Area Rusted, Per Cent 90 nil. Centrifuge Test, Separation, nil nil Per Cent: 1,500 R. P. 31., Room Temp. 2 Hr. UV Light Stability Quartz bright bright.

Tube 8Hr.:-Appearanee. Chevrolet 36 Hr. engine Test failed to com- 94-21.

CRO Designation C-4: Enplete test. gine Rating.

addition agents is sufficient to efiect the desired improvement. In view of their high molecular weight and low volatility at high,.temperatures, our new addition agents are particularly advantageous for preparing lubricants which en- ,6 I counter high temperatures, such as aviation lubricating oils.

The following examples illustrate-the use of our new addition agents to obtain improved mineral oil lubricant compositions.

Example III.An improved lubricating oil was prepared by blending a highly refined mineral lubricating oil with 1.0 per cent by weight of the compound prepared in accordance with Example I. A comparison of the properties of the base oil and improved oil follows:

Base Oil improved Oil Gravity, API. 25.8. Viscosity, SUV:

100 F 1,578. 210 F 117.5. Viscosity Index 99.

535. Fire,.OC, F 590. Pour, F 0 +5. Precipitation No nil.

passes.

Copper Strip Test, 212 F., 3 Hr. Corrosion Test, 'ASTM D665-46T Distilled Water:

Steel Rod, Appearance Area Rusted, Per Cent Falex Wear Test:

500 Lb. Gauge Load, 15 Min.-

Wear, No. of Teeth Gauge Load at Seizure, Lh

As shown in this example, the addition of our new agent inhibited rusting and also improved the pressure carrying properties.

Example IV.--An improved lubricatingoil was prepared by blending with a highly refined mineral lubricating oil 6 per cent by weight of the additive concentrate prepared in accordance with Example II. A comparison of the properties of the base oil and improved oil follows:

hyphen indicates the freedom from engine deposits expressed in per cent, the larger the per cent (approaching as a limit) the cleaner the engine. The marked improvement in detergent efiects obtained from the use of our new addition agent is clear. The figure to the right of the hyphen indicates the amount of bearing corrosion expressed in milligrams loss in weight of a standard bearing. Our new addition agent clearly confers excellent bearing corrosion-inhibiting properties. Finally, the above data show ance to oxidation, bearing corrosion and the.

deposition of contaminants resulting from decomposition and oxidation or other changes that occur in the lubricant in service. The procedure involves the intermittent operation of a special G-cylinder automotive test engine at constant speed and load for a total of 36 hours subsequent to a run-in period of 8 hours at graduated speeds and loads. Prior to each test, a complete set of new piston rings is installed and two new weighed copper-lead test bearings are installed in symmetrical location. Performance of the test oil is judged by examination of the power section of the engine for deposits and by ascertaining the weight loss of the test bearings.

While we have shown in the above examples the preparation of compounded lubricating oils, our invention is not limited thereto. but comprises all mineral oil lubricant compositions containing our new addition agents, such as greases and the like.

What we claim is:

l. A salt having the formula:

M o I on on cH,- on s a n n R wherein R is an alkyl radical having from 4 to 12 carbon atoms, and M is a divalent metal.

2. The salt of claim 1, wherein M is an alkaline earth metal.

3. The salt of claim 1, wherein M is calcium.

4. The salt of claim 1, wherein M is barium.

5. The salt of claim 1, wherein M is tin.

6. The salt of claim 1, wherein R is the tetra-,

methylbutyl radical.

7. A salt having the formula:

mol of a divalent metalsalt of a phenol having a para alkyl substituent of from- 4 to 12 carbon atoms, two mols of formaldehyde, .and one mol of a phenol disulfide obtained by reacting two mols of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms withfine mol of sulfur mono-chloride.

9. The process. whichcomprisescondensing at a temperature not greater than 275 F. one mol of a divalent metal salt of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms, two mols of formaldehyde, and one mol of a phenol disulflde obtained by reacting at a temperature ranging from room temperature to 350 F. two mols of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms with one mol of sulfur mono-chloride.

10. The process of claim 9, wherein the divalent metal salt is a calcium salt, and the para alkyl substituent of the phenol is the tetramethylbutyl radical.

11. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, suflicient to confer detergent properties on the composition, of a salt having the formula:

on on CHvOi-Q l R a wherin R is an alkyl radical having from 4 to 12 carbon atoms, and M is a divalent metal.

12. The composition of claim 11, wherein M is l R R an alkaline earth metal.

13. The composition of claim 11, wherein M is calcium.

14. The composition of claim 11, wherein M is barium;

15. The composition of claim 11, wherein M is tin.

16. The composition of claim 11, wherein R is the tetramethylbutyl radical.

17. The composition of claim 11, wherein the salt is present in an amount of from 0.1 to 10.0 per cent by weight on the mineral oil.

18. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, from 0.1 to 10.0 per cent by weight on the mineral lubricating oil, of a salt having the formula:

M o on I l l on -crr -r s wherein R is the tetramethylbutyl radical and M is a divalent metal..

19. The composition of claim 18, wherein M is calcium.

20. The composition of claim 18, wherein M is barium.

21. The composition of claim 18, wherein M is tin.

22. The process which comprises condensing at a temperature not greater than 275 F. in a mineral lubricating oil one mol of a divalent metal salt of a phenol having a para alkyl substituent of from 4 to 12 carbon atoms, two mols of formaldehyde. and one mol of a phenol disulflde obtained by reacting at a temperature ranging from room temperature to 350 F. two mols of a phenol having a para alkyl substituent of from 4 to 12 n'carbon mtoms with one mol of sulfur monochloride and recovering in solution in said mineral lubricating oil a. salt having the formula:

wherein R. is an alkyl radical having from 4 to 12 carbon atoms, and M is a, divalent metal.

TROY L. CANTRELL. HERSCHEL G. SMITH.

The following references are of record in the REFERENCES CITED file of this patent: 

